Re: Overwriting an uninitialized local variable in PHP

[Robert Larsen <robert () the-playground dk>]

Kellox wrote:

> A PHP script looks like this:
>
> $sort_mode = $_GET['sort'];
> if($sort_mode = 'ascendend') $query = "....";
> else if($sort_mode = 'descendend') $query = "....";
> ...
> mysql_query($query) or die();


> My question is if there is a way to "initialize" the variable $query
> myself as an attacker from the outside, so that I can write my on SQL
> query.

Yes. If PHP has been configured with "register_globals = On" or it is an
old version where this is the default you can do something like this:
http://vulnerablesite.com/vulnerable_script.php?sort=undefined&query=select
username, password from users

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